Can we call a film a film if there’s never any film involved? That’s one of the questions posed by Side by Side, a documentary that doubles as a movie lover’s wet dream. The doc examines the battle between traditional photochemical cinematography and digital cameras, rounding up just about every director you could possibly want to hear from on the subject: George Lucas, James Cameron, Martin Scorsese, Christopher Nolan, David Lynch, David Fincher, Danny Boyle, Steven Soderbergh…the list goes on and on.

Both sides of the debate are represented, and hearing David Fincher explain why he obviously prefers digital, followed by Christopher Nolan explaining why he obviously prefers celluloid hits a film geek’s brain directly in its pleasure center. But according to producer Justin Szlasa, the doc’s subject isn’t just for cinephiles. “I think there’s a lot that audiences don’t know about in terms of what kinds of decisions go into making a film,” he says “And we help explain it.” For example, the switch from film to digital also marks a shift in power, taking away from cinematographers the kremlinology of light-meters and dailies and putting more immediate power in the hands of directors.

The film’s other producer, some bearded dude named Keanu Reeves, also serves as its host. “Keanu did the majority of the interviews,” says director Christopher Kenneally. “And he geeked out as much as us. It was like, ‘Awesome, man, I get to meet David Lynch!’” Kenneally says Reeves also helped put the film’s interviewees at ease. “Within seconds, Keanu and Lars von Trier were laughing together,’ says Kenneally. “That seems like an accomplishment.’